The Cell and Immunology Core provides services that allow determination of effects of 1) drugs of abuse, 2) endogenous ligands which bind to the same receptors and transporters used by the drugs of abuse, or 3) infection with HIV or SIV or other opportunistic infections that are common in HIV, on cells of the immune system. The effects that are measured in the Core are functional endpoints which include responses of cells to mitogens; Natural Killer cell activity; capacity for in vitro antibody production; response in the Mixed Lymphocyte Reaction (MLR); and chemotaxis assays. In addition, the Core measures cytokine, chemokine, and neuropeptide levels in serum, plasma, cerebrospinal fluid, bronchial lavage fluid, peritoneal lavage fluid, or in supernatants of cell cultures, by a multiplex assay, or by ELISA assay for individual proteins. In addition, through support of the Flow Cytometry facility, the Core allows determination of effects of treatment with drugs of abuse or other related molecules, or infection, on numbers of immune cells in particular subsets, such as T-cells, CD4 and CD8 T-cells, B-cells, and monocyte/macrophages, Expression of cell surface markers, including receptors on primary cells or transfected cell lines, can also be quantitated on a per cell basis or as the percent of cells expressing a particular molecule. Intracellular expression of cytokines can be determined by flow cytometry. The Core also offers services to separate cells using magnetic bead technology, counter-current centrifugation using an elutriation centrifuge, or through sorting using the flow cytometer. Finally, the Core will screen cell lines for contamination with Mycoplasma.